One of many things you need to be careful about with E85 is the 85 moniker has very little to do with the actual ethanol content. Check out what the DOE say that you can label as E85, click here =>
"Handbook for Handling, Storing, and Dispensing E85 and Other Ethanol-Gasoline Blends"
The ethanol checking methodology available today, for the most part, is totally useless because it is measuring the gasoline content not the alcohol content. Having determined the gas content the sensor infers anything else is E85. This is misleading in the extreme and totally wrong head thinking about how to measure ethanol content. Even the flex fuel sensors from Detroit do the same thing. Check out this YouTube video illustrating the problem;
[ame="https://www.youtube.com/watch?v=8DZhLjwsWVY"]
Flex Fuel Sensor Testing[/ame]
As if this is not bad enough our engines are fueled using gravimetric measurements not volumetric measurements. Same as a Top Fuel car. A 90% Nitromethane/Methanol mix is 90% by weight and temperature corrected not 90% by volume. All DOE naming conventions for ethanol based fuels are volumetric, ignore water content and temperature. The difference at low power levels is just a loss of power. the difference at high power levels is parts failure.
Ethanol is hydroscopic, which means it leaches water out of the air around us — and it will if you expose it to the ambient atmosphere. Now you have a new facet of the problem which is the invisible water content of the fuel.
For performance engines if you intend to run ethanol (at any percentage) you ought to get a fuel source that has a high QC standard (not like the DOE) that the fuel must consistently meet to to be labelled E85 or E-whatever. Additionally you need to upgrade many of your fuel system components to survive the ethanol.
This is not as simple a transition as some think.
Ed